This invention relates to pumps for delivering medical fluids and particularly relates to peristaltic pumps for delivery of enteral nutrition fluids to a patient.
In accordance with known techniques the delivery of enteral nutrition fluids to a patient can be accurately controlled as to volumetric delivery rate by the use of a delivery system which includes a motor unit and a disposable delivery set. Likewise similar systems may be used for pumping of other fluids for medical purposes, such as intravenous infusion, blood pumping or supply of measured volumes of liquid medication to pre-loaded syringes or other containers.
In known systems for delivering enteral fluids the rate of fluid delivery is controlled by regulating the speed of a pump motor in accordance with the desired volume rate. Pump motor speed may be controlled, for example, by providing pulses to a stepper motor. Another system for providing variable rate fluid delivery makes use of a peristaltic pump with variable tension on the pump tube in combination with a constant speed motor.
In other known systems for pumping medical fluids there are provided means for monitoring rotation of the pump rotor, for example, by magnetic detection or by optical rotation detectors. In such systems the actual rotation rate of the motor is compared to the desired rotation rate for purposes of making corrections to the rotation rate of the motor. Alternately the motor may be operated to rotate the pump by a number of rotations corresponding to the desired volume.
It is an object of the present invention to provide a new and improved method for regulating the volumetric rate of fluid delivery in a medical fluid delivery system and to provide apparatus for carrying out the improved method.